Network Security

CSC332

Dr. Munam Ali Shah

PhD: University of Bedfordshire

MS: University of Surrey

M.Sc: University of Peshawar

Serving COMSATS since July 2004

Some Pictures

Park Square Campus, UoB, Luton

Putteridge Burry Campus, UoB, Luton

New Post Graduate Center, UoB, Luton

About the course

To provide a survey and exposure of both principles and practice of network security.

To determine threats to a network and how to protect organization’s systems and data from attacks.

The course will also help you understand and learn counter measures used to prevent, detect and correct security violations in a computer network.

You will NOT learn..

How to do computer hacking

Break in a computer server and gain access to sensitive data

Books and Resources

Cryptography and Network Security, 6th Edition by William Stallings

Network Secuirty Private Coomunication in a Public World, 2nd Edition by Charlie Kaufman, Radia Perlman, and Mike Speciner

How this course will be run

The course is comprised of 32 lectures and is divided in following parts:

Part - 1: Computer/System Security

Part - 2: Network Security

Part - 3: Internet Security

Part - 1: Computer/System Security

The main concepts that are discussed in this part are:

Security concepts, security violation categories, security measure levels, methods to violate security, types of attacks and firewalls.

This part will be covered in

Lecture 1 to Lecture 4

Part - 2: Network Security

This part is will cover most of the contents of the course. It has been further divided in following sub-parts:

a) Analysis of network security

b) Cryptography as a network security tool

c) Symmetric key cryptography

d) Asymmetric key cryptography

e) Incorporating security in other parts of the network

Part – 2 (a): Analysis of network security

Here we will discuss :

Network threats (viruses, worms, Trojan horse), countermeasures of the threats, network security model, access control, principles and techniques of network security with examples of how they are applied in practice.

The topics will be covered in

Lecture 5 - Lecture 8

Part – 2 (b): Cryptography as a network security tool

Topics covered in this part are:

Cryptography as a classical security tool, basic terminologies, steganography, substitution and transposition ciphers, Ceaser cipher

The topics will be covered in

Lecture 9 - Lecture 10

Part – 2 (c): Symmetric key cryptography

Topics covered in this part are:

Feistel cipher, Data Encryption Standard (DES), basic rounds, double and triple DES, Advanced Encryption Standard (AES) and limitations of the symmetric key cryptography.

The topics will be covered in

Lecture 11 - Lecture 17

Part – 2 (d): Asymmetric key cryptography

This part will cover the following topics:

Requirements and challenges for asymmetric key, Diffie-Hellman key exchange, Rivest Shamir & Adleman (RSA), attacks against RSA, hybrid cryptosystems and quantum cryptography.

The topics will be covered in

Lecture 18 - Lecture 23

Part – 2 (e): Incorporating security in other parts of the network

This part will discuss the following topics:

Overview of the network security protocols, e.g., Simple Network Management Protocol (SNMP), securing e-mail, wireless network security.

The topics will be covered in

Lecture 24 - Lecture 26

Part - 3: Internet Security

This is the last part of the course. The main concepts that are discussed in this part are:

Tools and techniques to protect data during the transmission over the Internet, Sobig F. worm, grappling Hook attack, Morris Internet worm, Overview of the Internet security protocols such as https and ssh.

This part will be covered in

Lecture 27 – Lecture 30

The last two lectures, i.e., Lecture 31 and 32 are reserved for the revision of the course.

Are you ready !!!!

Lets Begin

Lecture 1: Security Concept

Outlines

What is Security

Security violation categories

Security measure levels

Objectives

To describe the basics of a computer/systems security

To understand and distinguish between different

breaches of security.

The Security Problem

“A System is secure if resources are used and accessed as intended under all circumstances”

(Silberschatz, Galvin and Gagne)

There are four things to notice here

1- resources

2- used and accessed

3- as intended

4- in all circumstances

Some examples

A transmit a file (containing sensitive information) to B. C, who is not authorized to read the file, is able monitor the transmission

Administrator D sends a message to computer E for updating an authorization file. F intercept the message, alters its content to add or delete entries, and then forwards the message to E. E accept the message and update the authorization file

Rather than intercept, F constructs its own message and send it to E

Security Violation Categories

Breach of confidentiality

Unauthorized reading of data

Breach of integrity

Unauthorized modification of data

Breach of availability

Unauthorized destruction of data

Theft of service

Unauthorized use of resources

Denial of service (DOS)

Prevention of legitimate use

Security Measure Levels

Impossible to have absolute security, but make cost to perpetrator sufficiently high to deter most intruders

Security must occur at four levels to be effective:

Physical

Data centers, servers, connected terminals

Human

Avoid social engineering, phishing, dumpster diving

Operating System

Protection mechanisms, debugging

Network

Intercepted communications, interruption, DOS

Security is as weak as the weakest link in the chain

But can too much security be a problem?

Summary of today’s lecture

Today we learnt:

What is security and how different breaches of security can occur around us.

We have discussed how security breaches in a computing environment can occur at different levels.

Next Lecture contents

In next lecture we will learn about:

methods to violate security

types of security attacks

and concept of the firewalls

The End